Sequestering compositions and materials

ABSTRACT

The present disclosure relates to a composition that includes a sequestering material capable of binding a target material, where the sequestering material includes a first component that includes at least one of a functional group, a molecule, an oligomer, or a polymer, and the target material includes at least one of an element, a chemical, and/or a compound. In some embodiments of the present disclosure, the element may include at least one element from at least one of Rows 4, 5, 6, and 7 of the Periodic Table and/or an inner transition metal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional PatentApplication No. 62/853,951 filed May 29, 2019, the contents of which areincorporated herein by reference in their entirety.

CONTRACTUAL ORIGIN

This invention was made with government support under Contract No.DE-AC36-08G028308 awarded by the Department of Energy and Contract No.DMR-1806152 awarded by the National Science Foundation. The governmenthas certain rights in the invention.

SUMMARY

An aspect of the present disclosure is a composition that includes asequestering material capable of binding a target material, where thesequestering material includes a first component that includes at leastone of a functional group, a molecule, an oligomer, or a polymer, andthe target material includes at least one of an element, a chemical,and/or a compound. In some embodiments of the present disclosure, theelement may include at least one element from at least one of Rows 4, 5,6, and 7 of the Periodic Table and/or an inner transition metal. In someembodiments of the present disclosure, the element may include at leastone of cadmium, lead, tin, germanium, bismuth, thallium, chromium,mercury, antimony, and/or arsenic. In some embodiments of the presentdisclosure, the target material may include Pb²⁺.

In some embodiments of the present disclosure, the first component mayinclude at least one of hydrogen, phosphorus, nitrogen, sulfur, oxygen,carbon, and/or silicon. In some embodiments of the present disclosure,the first component may include at least one of a phosphonic group, aphosphate group, a phosphoryl group, a phosphono group, a phosphorgroup, and/or a phosphoryl group. In some embodiments of the presentdisclosure, the first component may have a structure defined by

where each of R₁, R₂, and R₃ include at least one of hydrogen, oxygen,and/or carbon. In some embodiments of the present disclosure, thestructure may be defined by

In some embodiments of the present disclosure, the first component mayinclude at least one of DMDP, EDTMP, dimercaptosuccinic acid (DMSA),ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA),ethylenediaminedisuccinic acid (EDDS), iminodisuccinic acid (IDS),methylglycine diacetic acid (MGDA), L-Glutamic acid N,Ndiacetic acid(GLDA), 2-hydroxyethyliminodiacetic acid (HEIDA),ethylenediamine-N,N′-dimalonic acid (EDDM),ethylenediamine-N,N′-diglutaric acid (EDDG),3-hydroxy-2,2-iminodisuccinic acid (HIDS), and/or 2,6-pyridinedicarboxylic acid (PDA), poly ethylene glycol (PEG), poly vinyl alcohol,poly vinyl pyrrolidone, and/or a cellulose-based material.

In some embodiments of the present disclosure, the sequestering materialmay further include a matrix material. In some embodiments of thepresent disclosure, the matrix material may include at least one of apolymer and/or an oligomer. In some embodiments of the presentdisclosure, the matrix material may include at least one of PVA, PEO, apolyacrylate, a derivative of a polyacrylate, polyvinylpyrrolidone, anoxide, a glass, and/or a silicone gel. In some embodiments of thepresent disclosure, the first component and the matrix material may bepresent at a first ratio between about 0.001 grams of the firstcomponent per gram of the matrix material and about 100 grams of thefirst component per gram of the matrix material.

In some embodiments of the present disclosure, the sequestering materialmay be substantially transparent to light having a wavelength betweenabout 300 nm and about 1200 nm. In some embodiments of the presentdisclosure, the sequestering material may have a solubility productconstant value, K_(sp), for the target material between about 10⁻⁶⁰ andabout 1. In some embodiments of the present disclosure, the sequesteringmaterial may have a capacity to absorb water at a second ratio betweenabout 0.01 grams of water per gram of the sequestering material andabout 100 grams of water per gram of the sequestering material. In someembodiments of the present disclosure, the composition may be used as atleast one of a coating or a paint.

An aspect of the present disclosure is a device that includes a firstfeature that includes a sequestering material, and a second feature thatincludes a target material, where the sequestering material is capableof binding the target material, the sequestering material includes afirst component that includes at least one of a functional group, amolecule, an oligomer, and/or a polymer, and the target materialincludes at least one of an element, a chemical, and/or a compound. Insome embodiments of the present disclosure, the first feature mayinclude a first planar structure, the second feature may include asecond planar structure, where the first planar structure and the secondplanar structure may be adjacent and substantially parallel to oneanother.

An aspect of the present disclosure is a method for sequestering atarget material, where the method incudes applying a composition thatincludes a sequestering material to a device having a feature thatincludes the target material, where over a period of time, a portion ofthe target material is removed from the feature due to exposure to theenvironment, and the sequestering material binds the portion of thetarget material, preventing its leakage into the environment.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments are illustrated in referenced figures of the drawings.It is intended that the embodiments and figures disclosed herein are tobe considered illustrative rather than limiting.

FIG. 1A illustrates a schematic of Pb-sequestering layers on both thefront (glass) and back (metal electrode) sides of a standard n-i-pperovskite solar cell (FTO glass/TiO₂/perovskite/spiro-OMeTAD/Au),according to some embodiments of the present disclosure. A first layerof P,P′-di(2-ethylhexyl)methanediphosphonic acid (DMDP) as asequestering material was coated on the glass side and a second layer ofN,N,N′,N′-ethylenediaminetetrakis(methylenephosphonic acid) andpolyethylene oxide (EDTMP-PEO) as a sequestering material was added onthe metal electrode side, which was further covered by ethylene vinylacetate (EVA) to provide a sealant, according to some embodiments of thepresent disclosure.

FIG. 1B illustrates the optical transmittance of a glass substrate witha DMDP layer (lighter line) and without a DMDP layer (darker line),according to some embodiments of the present disclosure.

FIG. 1C illustrates a comparison of the J-V characteristics of deviceslacking layers of sequestering materials (data set with circles),devices having a single layer of sequestering material on the glass-side(triangles), and devices with the PSC stack positioned between twolayers of sequestering materials (diamonds), according to someembodiments of the present disclosure. Solid markers (circles,triangles, and diamonds) correspond to forward scans; hollow markerscorrespond to reverse scans.

FIG. 1D illustrates the operational stability for devices withPb-sequestering layers and without Pb-sequestering layers, according tosome embodiments of the present disclosure. All devices were covered bya layer of EVA sealant, according to some embodiments of the presentdisclosure. The data sets are marked the same as the data sets of FIG.1C.

FIG. 2 illustrates the optical transmittance of DMDP films acting aslead-sequestering materials, with varying DMDP film thicknesses coatedon glass, according to some embodiments of the present disclosure. TheDMDP film thickness was varied from 0.7 to 6.89 μm. The numbers in thelegend correspond to the thickness of the DMDP films in micrometers. Theinset shows a magnified view of the transmittance spectra.

FIG. 3 illustrates the effects of the presence of packaging layers ofEVA on the J-V curves of perovskite solar cells, data sets for solarcells with EVA layers and without EVA layers on the metal electrode sideof the device, according to some embodiments of the present disclosure.Both forward and reverse voltage scans are shown. No clear effect oncell efficiency as a result of the EVA film is observed. Square markersrepresent devices lacking an EVA packaging layer; circular markersrepresent devices having an EVA packaging layer. Hollow markersrepresent reverse scans; solid markers represent forward scans.

FIG. 4 illustrates the lead-sequestering capacity of sequesteringmaterials made of mixtures of matrix materials (PEO and poly(vinylalcohol) (PVA)) and EDTMP, specifically the lead-sequesteringcapabilities of lead-sequestering films made of various EDTMP-containingmixtures prepared by various methods and used as backside (metalelectrode side) lead-sequestering layers, according to some embodimentsof the present disclosure. The area of all the films was 2 cm×2 cm. TheEDTMP-containing materials were soaked in 50 mL aqueous PbI₂ solutionshaving a lead concentration of 7 ppm. “5% PEO in DI” stands for anEDTMP-containing film prepared by dissolving 5 wt % polyethylene oxide(i.e. matrix material) in deionized water (DI) as a solvent, followed bythe adding and mixing of the EDTMP. The mixture was then applied as athin film by a doctor blade coating method with such an area that theconcentration of EDTMP was about 0.01 g/cm². The film was desiccated andcut into the desired shape and size. ACN=acetonitrile as a solvent.

FIG. 5 illustrates IPCE spectra of devices with and withoutlead-sequestering layers, according to some embodiments of the presentdisclosure. The current densities obtained from integrated IPCE spectraare consistent with the J-V measurement. The data sets are marked thesame as the data sets of FIGS. 1C and 1D.

FIG. 6 illustrates stable power output (SPO) near the maximum powerpoint of devices with and without lead-sequestering layers, according tosome embodiments of the present disclosure. The SPO efficiencies areconsistent with the efficiencies determined from the J-V measurement.The data sets are marked the same as the data sets of FIGS. 1C and 1D.

FIG. 7A illustrates statistics for the PCE of devices with and withoutlead-sequestering layers, according to some embodiments of the presentdisclosure. (Legend: circle=control (no sequestering materials);triangle=DMDP sequestering layer on the glass side; diamond=DMDPsequestering layer on the glass side and EDTMP-PEO sequestering layer onthe metal electrode side.)

FIG. 7B illustrates statistics for the J_(sc) of devices with andwithout lead-sequestering layers, according to some embodiments of thepresent disclosure. The data sets are marked the same as specified forFIG. 7A.

FIG. 7C illustrates statistics for the V_(oc) of devices with andwithout lead-sequestering layers, according to some embodiments of thepresent disclosure. The data sets are marked the same as specified forFIG. 7A.

FIG. 7D illustrates statistics for the FF of devices with and withoutlead-sequestering layers, according to some embodiments of the presentdisclosure. The data sets are marked the same as specified for FIG. 7A.

FIG. 8A illustrates lead concentrations released from devices (sixtotal) damaged on both sides, without any lead-sequestering materialsafter being immersed in 40 mL water for 3 hours. The concentrations ofdissolved lead from these devices were slightly higher than thecalculated values based on the density and thickness of the perovskitelayers due to the slightly excessive amount of PbI₂ used in theprecursor solutions.

FIG. 8B illustrates the device architecture of a perovskite-containingsolar cell that was tested without the presence of layers oflead-sequestering materials.

FIG. 9 illustrates a verification curve of prepared lead concentrationsof various PbI₂ solutions and the measured concentrations by flameatomic absorption spectrometer (FAAS). The result shows excellentaccuracy and precision of the measurement system.

FIG. 10 illustrates the lead-sequestering performance as a function ofimmersion time for DMDP layers coated on glass substrates with differentthicknesses, according to some embodiments of the present disclosure.The DMDP layer thicknesses are indicated in micrometers. All of the DMDPcoated glass substrates were immersed in 50 mL of a 1.93×10⁻⁵ M PbI₂aqueous solution (equivalent to a total of 9.65×10⁻⁷ mol Pb²⁺ or 4 ppmof Pb²⁺, while the maximum solubility of PbI₂ in 50 ml water is about8.20×10⁻⁵ mol at room temperature) to test the lead-sequesteringcapabilities of these samples.

FIG. 11A illustrates of photographs PSCs damaged as described herein.

FIG. 11B summarizes the amount of lead released from the damaged devicesshown in FIG. 11A.

FIG. 11C illustrates the final distribution of lead at various possiblelocations in the damaged devices and to the local environment (water),for the damaged devices shown in FIG. 11A. These data are summarized inTable 2 below.

FIG. 12 illustrates the effect on the lead-sequestration abilities ofdamaged devices at room temperature, according to some embodiments ofthe present disclosure. The table provides a legend for each data setillustrated in the top figure.

FIG. 13 illustrates the effect on the lead-sequestration abilities ofdamaged devices at 50° C., according to some embodiments of the presentdisclosure. The table provides a legend for each data set illustrated inthe top figure.

FIG. 14 illustrates molecular modeling results of the bindingconfigurations of Pb²⁺ ions with deprotonated DMDP and EDTMP, accordingto some embodiments of the present disclosure. Configurations wereobtained based on density functional theory calculations.

FIG. 15A illustrates a schematic of a method for producingperovskite-containing solar cells that include layers of sequesteringmaterials, according to some embodiments of the present disclosure.

FIG. 15B compares a pristine device (left) and a device treated with theDMDP solution (right) showing that directly applying the DMDP in ethanolsolution damaged the perovskite stack, with the damage indicated by theyellowing associated with perovskite decomposition due to the polarethanol.

FIG. 16A illustrates lead leakage from devices in acidic water at roomtemperature, according to some embodiments of the present disclosure.

FIG. 16B illustrates lead leakage from devices in acidic water at 50°C., according to some embodiments of the present disclosure.

FIG. 16C illustrates the impact of competitive ion (Ca²⁺) on leadsequestration by DMDP, according to some embodiments of the presentdisclosure.

FIG. 16D illustrates the impact of competitive ion (Ca²⁺) on leadsequestration by EDTMP-PEO, according to some embodiments of the presentdisclosure.

FIG. 16E illustrates a photograph of custom-made apparatus to study leadleakage from damaged devices under flowing water to simulate a rainingcondition, according to some embodiments of the present disclosure.

FIG. 16F illustrates a comparison of Pb-sequestration efficiency ofdevices at room temperature under flowing pure water (left) and acidicwater at a pH of about 4.2 (right), according to some embodiments of thepresent disclosure.

REFERENCE NUMBERS

100 device 110 layer of sequestering material 115 packaging layer 120stack 122 conducting layer 124 hole transport layer 126 electrontransport layer 128 active layer 129 conducting layer

DETAILED DESCRIPTION

The embodiments described herein should not necessarily be construed aslimited to addressing any of the particular problems or deficienciesdiscussed herein.

References in the specification to “one embodiment”, “an embodiment”,“an example embodiment”, “some embodiments”, etc., indicate that theembodiment described may include a particular feature, structure, orcharacteristic, but every embodiment may not necessarily include theparticular feature, structure, or characteristic. Moreover, such phrasesare not necessarily referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with an embodiment, it is submitted that it is within theknowledge of one skilled in the art to affect such feature, structure,or characteristic in connection with other embodiments whether or notexplicitly described.

As used herein the term “substantially” is used to indicate that exactvalues are not necessarily attainable. By way of example, one ofordinary skill in the art will understand that in some chemicalreactions 100% conversion of a reactant is possible, yet unlikely. Mostof a reactant may be converted to a product and conversion of thereactant may asymptotically approach 100% conversion. So, although froma practical perspective 100% of the reactant is converted, from atechnical perspective, a small and sometimes difficult to define amountremains. For this example of a chemical reactant, that amount may berelatively easily defined by the detection limits of the instrument usedto test for it. However, in many cases, this amount may not be easilydefined, hence the use of the term “substantially”. In some embodimentsof the present invention, the term “substantially” is defined asapproaching a specific numeric value or target to within 20%, 15%, 10%,5%, or within 1% of the value or target. In further embodiments of thepresent invention, the term “substantially” is defined as approaching aspecific numeric value or target to within 1%, 0.9%, 0.8%, 0.7%, 0.6%,0.5%, 0.4%, 0.3%, 0.2%, or 0.1% of the value or target.

As used herein, the term “about” is used to indicate that exact valuesare not necessarily attainable. Therefore, the term “about” is used toindicate this uncertainty limit. In some embodiments of the presentinvention, the term “about” is used to indicate an uncertainty limit ofless than or equal to ±20%, ±15%, ±10%, ±5%, or ±1% of a specificnumeric value or target. In some embodiments of the present invention,the term “about” is used to indicate an uncertainty limit of less thanor equal to ±1%, ±0.9%, ±0.8%, ±0.7%, ±0.6%, ±0.5%, ±0.4%, ±0.3%, ±0.2%,or ±0.1% of a specific numeric value or target.

As used herein, the term “photovoltaic device” includes solar cells,solar panels, solar modules, and/or solar arrays. In addition, a“photovoltaic device” may include at least one of a photovoltaicallyactive material, a charge-transport material, a current collectingmaterial, a reflecting material, and/or any other material and/orelements utilized in a particular photovoltaic device design. Furtherexamples of features potentially contained in devices utilizing at leastone of the element- and/or molecule-sequestering compositions and/ormaterials described herein include busbars, solder, welds, frontshielding glass, encapsulant materials, insulating back sheets, backcover layers, and/or other support structures. A “photovoltaic device”may include single-junction and/or multiple-junction devices. As usedherein, the term “feature” refers to a distinct physical part of adevice and/or a material and/or a composition used to construct adevice. As used herein, the term “sequestering material” refers to amolecule, oligomer, polymer, composition, and/or mixture that is capableof capturing, absorbing, adsorbing, and/or reacting with at least onetarget material, resulting in the sequestration of the target materialwithin and/or on a surface of the sequestering material. As used herein,the term “target material” refers to any element, chemical, and/orcompound whose release into the environment from a particularmanufactured device is undesirable.

The term “polymer”, as used herein, refers to a molecule of highrelative molecular mass, the structure of which comprises the multiplerepetition of units derived, actually or conceptually, from molecules oflow relative molecular mass. In certain embodiments, a polymer iscomprised of only one monomer species (e.g., polyethylene oxide). Incertain embodiments, a polymer of the present invention is a copolymer,terpolymer, heteropolymer, block copolymer, or tapered heteropolymer ofone or more epoxides. The term “oligomer” refers to a moleculeconstructed of monomer species similar to a polymer, but having a lowermolecular mass, relative to a polymer.

The present disclosure relates to sequestering materials, compositionscontaining sequestering materials, and/or devices containingsequestering materials, capable of sequestering various targetmaterials, in the form of elements, compounds, ions, and/or molecules,contained within one or more features of a device, including, amongother elements, metals and/or metalloids. Metals, as an example of thetarget materials, include at least one of main group metals, transitionmetals, and/or inner transition metals. As described herein,sequestering materials, compositions and/or devices may minimize and/oreliminate the migration of harmful metals from these materials,compositions, and/or devices into the environment. Some examples oftarget materials that may be sequestered using some embodiments of thesequestering materials, compositions, and/or devices described hereininclude at least one of lead, tin, germanium, cadmium, copper, indium,gallium, mercury, bismuth, chromium, iron, copper, zinc, aluminumberyllium, ruthenium, nickel, cobalt, manganese, silver, thallium,indium, antimony, germanium, selenium, tellurium, and/or arsenic (anexample of a metalloid), iodine, bromine, chlorine, and/or fluorine.Some embodiments of the present disclosure may be utilized to sequesterelements and/or molecules contained in photovoltaic devices,light-emitting diodes (LEDs), solar windows, sensors, displays, X-raydetectors, memristors and/or any other metal-containing and/ormetalloid-containing electronic devices and optoelectronic devices, aswell as non-electronic metal-containing objects such as pipes and/ormetal-containing surfaces such as walls, ceilings, and/or floors coatedwith lead-containing paint. The elements and/or molecules sequestered bythe materials and compositions described herein may be in any valencestate (e.g. Pb²⁺).

In some embodiments of the present disclosure, only one feature of anelectronic device may utilize at least one of the sequestering materialsdescribed herein. For example, only an active layer of a solar cell,containing the element and/or molecule to be sequestered (i.e. targetmaterial), may utilize at least one of the sequestering materialsdescribed herein; e.g. the active layer may be substantiallyencapsulated by a sequestering material. In some embodiments of thepresent disclosure, more than one feature of an electronic device mayutilize at least one of the sequestering materials described herein. Forexample, an active layer and a charge-transport layer of a photovoltaicdevice may both utilize at least one of the sequestering materialsdescribed herein; e.g. both the active layer and the charge-transportlayer may be substantially encapsulated by a sequestering material.Similarly, other electronic devices (e.g. LEDs, sensors, displays, etc.)may contain one or more features having the target material to besequestered that utilize at least one of the sequestering materialsdescribed herein. Thus, in some embodiments of the present disclosure,any device and/or feature of a device containing a hazardous elementand/or material (i.e. target material) may be at least partially coveredand/or encapsulated by the sequestering materials described herein, suchthat the hazardous element and/or material is not released into theenvironment during the life-span of the device and/or its time spent inthe environment.

In some embodiments of the present disclosure, a feature of a device mayinclude a material having an element and/or molecule to be sequestered(e.g. an active material), where a sequestering material and/orcomposition is mixed with the material containing the target material toform a composite material. In some embodiments of the presentdisclosure, a sequestering material may form a single homogenous phase(e.g. solid phase and/or liquid phase) with the material it is mixedwith. In some embodiments of the present disclosure, a sequesteringmaterial may form a heterogeneous phase (e.g. solid phase and/or liquidphase) with the material it is mixed with. For example, a sequesteringmaterial may be dispersed as a first solid phase in a second continuoussolid phase of a material containing the target material to besequestered. Alternatively, a sequestering material may be a firstcontinuous solid phase, with the material (containing the targetmaterial) it is mixed with dispersed as a second solid phase within thecontinuous solid phase of the sequestering material.

In another example, a feature of an electronic device constructed of amaterial containing a target material, e.g. an element and/or molecule,to be sequestered may have a surface that is adjacent to a sequesteringmaterial. As used herein, the term “adjacent” refers to two featuresthat are either in direct physical contact and/or closely associatedwith each other. For example, a first layer adjacent to a second layermay be in direct physical contact or there may be at least oneintervening layer positioned between the first layer and the secondlayer. Thus, in some embodiments of the present disclosure a device maybe constructed as a three-dimensional object and/or include athree-dimensional feature having one or more external surfaces, withexamples including amorphous particles, planar structures, spheres,cylinders, cuboids, cones, pyramids, polyhedrons, and/or any other shaperequired for a specific device and/or application. In some embodimentsof the present disclosure, at least one surface of a device and/orfeature of a device may be positioned adjacent to a sequesteringmaterial. For example, the outer surface of a particle containing atarget material to be sequestered may be substantially coated with asequestering material. In another example, a surface of a planar devicecontaining a target material may be positioned adjacent to a layerincluding a sequestering material. In another example, a surface of aplanar device containing a target molecule may be positioned between afirst layer and a second layer, where both the first layer and thesecond layer include a sequestering material. In some embodiments of thepresent disclosure, an intervening layer may be substantially permeableto the targeted material. In some embodiments of the present disclosure,an intervening layer may be substantially impermeable to the targetedmaterial.

Examples of active materials that may utilize at least one of thesequestering materials described herein include, but are not limited to,at least one of a perovskite, a quantum dot (i.e. nanocrystal), apolymer, and/or an alloy, with or without at least one metal. Examplesof perovskites include perovskites described by the general formulaABX₃, where X is an anion and A and B are cations. In some embodimentsof the present invention, the A-cation may include a nitrogen-containingorganic compound such as an alkyl ammonium compound. The B-cation mayinclude a metal and the X-anion may include a halogen. Additionalexamples for the A-cation include organic cations and/or inorganiccations, for example Cs, Rb, K, Na, Li, and/or Fr. Organic A-cations maybe an alkyl ammonium cation, for example a C₁₋₂₀ alkyl ammonium cation,a C₁₋₆ alkyl ammonium cation, a C₂₋₆ alkyl ammonium cation, a C₁₋₅ alkylammonium cation, a C₁₋₄ alkyl ammonium cation, a C₁₋₃ alkyl ammoniumcation, a C₁₋₂ alkyl ammonium cation, and/or a C₁ alkyl ammonium cation.Further examples of organic A-cations include methylammonium (CH₃NH₃ ⁺),ethylammonium (CH₃CH₂NH₃ ⁺), propylammonium (CH₃CH₂ CH₂NH₃ ⁺),butylammonium (CH₃CH₂ CH₂ CH₂NH₃ ⁺), formamidinium (NH₂CH═NH₂ ⁺),hydrazinium, acetylammonium, dimethylammonium, imidazolium, guanidiniumand/or any other suitable nitrogen-containing and/or organic compound.In other examples, an A-cation may include an alkylamine. Thus, anA-cation may include an organic component with one or more amine groups.In some cases, the organic constituent may be an alkyl group such asstraight-chain or branched saturated hydrocarbon group having from 1 to20 carbon atoms. In some embodiments, an alkyl group may have from 1 to6 carbon atoms. Examples of alkyl groups include methyl (C₁) ethyl (C₂),n-propyl (C₃), isopropyl (C₃), n-butyl (C₄), tert-butyl (C₄), sec-butyl(C₄), iso-butyl (C₄), n-pentyl (C₅), 3-pentanyl (C₅), amyl (C₅),neopentyl (C₅), 3-methyl-2-butanyl (C₅), tertiary amyl (C₅), and n-hexyl(C₆). Additional examples of alkyl groups include n-heptyl (C₇), n-octyl(C₈) and the like.

Examples of metal B-cations include, for example, lead, tin, germanium,and or any other 2+ valence state metal that can charge-balance theperovskite. Further examples include transition metals in the 2+ statesuch as Mn, Mg, Zn, Cd, and/or lanthanides such as Eu. B-cations mayalso include elements in the 3+ valence state, as described below,including for example, Bi, La, and/or Y. Examples of X-anions includehalogens: e.g. fluorine, chlorine, bromine, iodine and/or astatine. Insome cases, the perovskite halide may include more than one X-anion, forexample pairs of halogens; chlorine and iodine, bromine and iodine,and/or any other suitable pairing of halogens. In other cases, theperovskite may include two or more halogens of fluorine, chlorine,bromine, iodine, and/or astatine.

Thus, the A-cation, the B-cation, and X-anion may be selected within thegeneral formula of ABX₃ to produce a wide variety of perovskites,including, for example, methylammonium lead triiodide (CH₃NH₃PbI₃), andmixed halide perovskites such as CH₃NH₃PbI_(3−x)Cl_(x) andCH₃NH₃PbI_(3−x)Br_(x). Thus, a perovskite may have more than one halogenelement, where the various halogen elements are present in non-integerquantities; e.g. x is not equal to 1, 2, or 3. In addition, perovskitehalides, like other organic-inorganic perovskites, can formthree-dimensional (3-D), two-dimensional (2-D), one-dimensional (1-D) orzero-dimensional (0-D) networks, which may possess the same unitstructure. As described herein, the A-cation of a perovskite, mayinclude one or more A-cations, for example, one or more of cesium, FA,MA, etc. Similarly, the B-cation of a perovskite, may include one ormore B-cations, for example, one or more of lead, tin, germanium, etc.Similarly, the X-anion of a perovskite 100 may include one or moreanions, for example, one or more halogens. Any combination is possibleprovided that the charges balance.

Further, a perovskite in at least one of a cubic, orthorhombic, and/ortetragonal structure, may have other compositions resulting from thecombination of the cations having various valence states in addition tothe 2+ state and/or 1+ state described above for lead and alkyl ammoniumcations; e.g. compositions other than AB²⁺X₃ (where A is one or morecations, or for a mixed perovskite where A is two or more cations).Thus, the methods described herein may be utilized to create novel mixedcation materials having the composition of a double perovskite(elpasolites), A₂B¹⁺B³⁺X₆, with examples of such a composition beingCs₂BiAgCl₆ and Cs₂CuBiI₆. Another example of a composition within thescope of the present disclosure is described by A₂B⁴⁺X₆, for exampleCs₂PbI₆ and Cs₂SnI₆. Yet another example is described by A₃B₂ ³⁺X₉, forexample Cs₃Sb₂I₉. For each of these examples, A is one or more cations,or for a mixed perovskite, A is two or more cations. Another example ofa composition within the scope of the present disclosure is 2D layeredperovskites, which are generally described by M₂A_(n−1)B_(n)X_(3n+1),where M is a large cation, such as BA=butylammonium,PEA=phenylethylammonium, CA=cyclopropylammonium, PEI=polyethylenimine,IEA=iodoethylammonium, EDA=ethane-1,2-diammonium, or AVA=ammoniumvalericacid; A is methylammonium (MA), formamidinium (FA), or Cs; B is Pb orSn; X is a halide anion, namely, I, Br, or Cl; and n is the number oflayers of metal halide sheets. The limit of n=∞ corresponds to the 3Dperovskite.

In some embodiments of the present disclosure, a device that includessequestering materials may include features that include quantum dots(i.e. nanocrystal). In some embodiments of the present disclosure, aquantum dot may be constructed of various semiconducting alloys,including, for example, Pb Se, PbS, CdSe, CdS, CdTe, and/or other Pband/or Cd containing materials. Other active materials include CdTe, Si,I-III-VI₂ compounds such as CuIn_(x)Ga_(1−x)Se₂, where x may be between0 and 1, inclusively, and III-V compounds such as GaAs. In someembodiments of the present disclosure, a device may include more thanone active material, such as in multiple-junction photovoltaic devices.

In some embodiments of the present disclosure, a sequestering material(e.g. metal-sequestering composition) may include a compound configuredto interact with a metal by at least one of chelation, binding,reacting, ionically interacting, and/or physically adsorbing the metal.As used herein, the terms “binding” and “bonding” refer to charge-chargeinteractions between neighboring atom, ions, and/or molecules. As usedherein, the term “chelating” refers to a type of bonding of ions andmolecules to metal ions, which involves the formation or presence of twoor more separate coordinate bonds between a polydentate (multiplebonded) ligand and a single central atom. These ligands are calledchelants, chelators, chelating agents and/or extractants, which caninclude organic compounds. In some embodiments of the presentdisclosure, a sequestering material for sequestering a target materialmay include at least one of a ketone, an aldehyde, a carboxylic acid, anester, an ether, and/or a carbonate. In some embodiments of the presentdisclosure, a sequestering material for sequestering an element and/ormolecule may include at least one of hydrogen, phosphorus, nitrogen,sulfur, oxygen, carbon, and/or silicon.

For example, a sequestering material may include at least one of anamine group, an amide group, a hydrazine group, an isocyanate group, anitrile group, and/or a nitrite group. Additional nitrogen-containinggroups that may sequester a metal include at least one of an amino group(primary, secondary, and/or tertiary), an imino group, an imido group, ahydrazine group, a cyanate group, an isocyano group, anisocyanato-nitrooxy group, a cyano group, a nitrosooxy group, a nitrosogroup, a pyridyl group, and/or a carboxamido group. Sulfur-containinggroups that may sequester a metal include at least one of a thiol group,a sulfide group, a disulfide group, a sulfoxide group, a sulfone group,a sulfinic acid group, a sulfonic acid group, a thiocyanato group, amercapto group, a sulfanyl group, a sulfinyl group, a sulfo group, asulfonyl group, an isothiocyanato group and/or a disulfide group.Phosphorus-containing groups that may sequester an element and/ormolecule include at least one of a phosphonic group, a phosphate group,a phosphoryl group, a phosphono group, a phosphor group, and/or aphosphoryl group. Carbon-containing groups that may sequester a metalinclude at least one of a C—OH group (carbon hydroxyl group), a carbonylgroup, a carboxylate group. Silicon-containing groups that may sequestera metal include at least one of a silicate group, a siliconate group, asilane group, or a siloxane.

In some embodiments of the present disclosure, a sequestering materialmay include a compound having a structure defined by

where at least one of R₁, R₂, and/or R₃ comprise at least one ofhydrogen, oxygen, and/or carbon. For example, at least one of R₁, R₂,and/or R₃ may include at least one of an oxygen-containing group, ahydroxyl group, and/or an alkyl group.

In some embodiments of the present disclosure, a sequestering materialmay include a compound having a structure defined by

where at least one of R₄ and/or R₅ comprise at least one of hydrogen,oxygen, and/or carbon. For example, at least one of R₄ and/or R₅ mayinclude at least one of an oxygen-containing group, a hydroxyl group,and/or an alkyl group.

In some embodiments of the present disclosure, a sequestering materialmay include a compound having a structure defined by

where at least one of R⁶ and/or R comprise at least one of hydrogen,oxygen, and/or carbon. For example, at least one of R⁶ and/or R mayinclude at least one of an oxygen-containing group, a hydroxyl group,and/or an alkyl group. In some embodiments of the present disclosure, acomposition for sequestering an element and/or molecule may includeP,P′-di(2-ethylhexyl)methanediphosphonic acid (DMDP) having a structuredefined by

In some embodiments of the present disclosure, a composition forsequestering an element and/or molecule may includeN,N,N′,N′-ethylenediaminetetrakis(methylenephosphonic acid) (EDTMP)having a structure defined by

In some embodiments of the present disclosure, a sequestering materialmay include at least one of P,P′-di(2-ethylhexyl)methanediphosphonicacid (DMDP) and/or N,N,N′,N′-ethylenediaminetetrakis(methylenephosphonicacid) (EDTMP). Other sequestering compositions that fall within thescope of the present disclosure include at least one ofdimercaptosuccinic acid (DMSA), ethylenediaminetetraacetic acid (EDTA),nitrilotriacetic acid (NTA), ethylenediaminedisuccinic acid (EDDS),iminodisuccinic acid (IDS), methylglycine diacetic acid (MGDA),L-Glutamic acid N,Ndiacetic acid (GLDA), 2-hydroxyethyliminodiaceticacid (HEIDA), ethylenediamine-N,N′-dimalonic acid (EDDM),ethylenediamine-N,N′-diglutaric acid (EDDG),3-hydroxy-2,2-iminodisuccinic acid (HIDS), and/or 2,6-pyridinedicarboxylic acid (PDA), poly ethylene glycol (PEG), poly vinyl alcohol,poly vinyl pyrrolidone and cellulose-based materials.

In some embodiments of the present disclosure, a sequestering materialmay have a capacity to sequester between 0.001 grams and 100 grams ofthe target material being sequestered per gram of the sequesteringmaterial, or between 0.01 grams and 10 grams per gram of thesequestering material. In some embodiments of the present disclosure, anelemental target material that may be sequestered by a sequesteringmaterial described herein includes elements from at least one of Rows 4,5, 6, and/or 7 of the Periodic Table and/or an inner transition metal.For example, an element that may be sequestered by the sequesteringmaterials described herein include at least one of cadmium, lead, tin,germanium, bismuth, thallium, chromium, mercury, antimony, and/orarsenic.

In some embodiments of the present disclosure, a sequestering materialfor sequestering a target material (e.g. an element and/or molecule) mayfurther include a matrix material constructed of at least one of anorganic material and/or an inorganic material. In some embodiments ofthe present disclosure, a sequestering material may be at least one ofcovalently bonded and/or ionically bonded to a matrix material. Forexample, a matrix material may include a polymer such as at least one ofpoly(vinyl alcohol) (PVA), poly(ethylene oxide) (PEO), a polyacrylateand/or its derivatives, and/or polyvinylpirrolidone. In some embodimentsof the present disclosure, a matrix material may include at least one ofan inorganic material and/or an organic-inorganic hybrid material suchas an oxide, a glass and/or a silicone gel. Thus, as described herein, asequestering material may include a first component, as described above,that has the ability to sequester a target material and a matrixmaterial that among other things, may provide structural integrityand/or additional sequestering capacity for the target material.

In some embodiments of the present disclosure, a matrix material mayhave a capacity to absorb at least one of water, an aqueous liquid,and/or an aqueous solution. For example, water absorbed by a matrixmaterial may include at least one of acidic water, basic water,deionized water, filtered water, and/or any naturally occurring water(e.g. rainwater, dew, fresh water, sea water, etc.). In some embodimentsof the present disclosure, a matrix material may have a water capacitybetween about 0.1 gram of water per gram of matrix material and about100 g of water per gram of matrix material. In some embodiments of thepresent disclosure, the capability to absorb water may enable and/orassist the sequestering material to sequester metal in water and preventthe migration of metal into the environment. The matrix materials mayswell, rather than dissolve, when exposed to water; e.g. when the matrixmaterial is submerged in standing water. This may enable thesequestering material to retain its structural integrity for subsequenthandling, such as when recovering the target materials (e.g. metals)from the sequestering material and/or the sequestering material and itscorresponding matrix material. In some embodiments of the presentdisclosure, a ratio of the sequestering material to the matrix materialmay be between about 0.01 grams of the sequestering material per gram ofmatrix material and about 10 grams of the sequestering material per gramof matrix material. In some embodiments of the present disclosure, asequestering material and/or matrix material may be transparent tolight. For example, a sequestering material and/or matrix material maybe transparent to light having a wavelength between about 300 nm andabout 1200 nm.

Thus, some embodiments of the present disclosure relate to perovskitesolar cells (PSCs), which promise a high-efficiency and low-costalternative in comparison to other photovoltaic (PV) technologies.However, PSCs can present toxicity challenges due to many perovskiteformulations containing, among other elements, tin and/or lead. Ratherthan eliminating these elements from the perovskite materials, whichwould negatively impact the PV performance, the present disclosureprovides a cost-effective solution to eliminate and/or minimize the lossof toxic elements and/or molecules from the PSC devices to theenvironment, while maintaining good PV performance metrics. Therefore,in general, the compositions, materials, devices and/or methodsdescribed herein provide in-situ passivation of leaked toxic materials(e.g. lead and/or tin) from devices containing these toxic materials.For example, in some embodiments of the present disclosure, alead-containing perovskite layer (where lead is the target material) maybe positioned between two layers containing a lead-sequesteringmaterial. For example, lead-sequestering materials may include stronglead-binding compounds, such as chelating agents for metal ions (e.g.Pb²⁺). In some embodiments of the present disclosure, as describedherein, a sequestering material may include covalently linked chemicalfunctional groups that have a very small solubility product constantvalue, K_(sp), for the target materials (e.g. lead ions), e.g. K_(sp)between 10⁻⁶⁰ and 1, with examples of functional groups includingphosphonic acid and/or sulfonic acid groups. In general, the lower thevalue of K_(sp), the greater the sequestration effect offered by thesequestering material. SP stand for “solubility product”.

In addition, for the side that light (e.g. sunlight) enters a PV device,transparent sequestering materials (e.g. lead-sequestering compositions)may be used so that the sequestering materials do not negatively impactthe light-harvesting capabilities of the devices. In addition, someembodiments of the sequestering materials described herein may beinsoluble in water while simultaneously providing a high capacity toabsorb water with a high swelling ratio, such that the sequesteringmaterials maintain their structural integrity, even when immersed inwater. To achieve this, as described above, some embodiments of thepresent disclosure may include a matrix material that includes, amongother things, at least one of a polymer and/or a molecule constructed oforganic-inorganic compositions that form robust, high swelling ratestructures (e.g. films) in the presence of water. As described above, insome embodiments of the present disclosure, a matrix material itself maybe the sequestering material, where sequestering functional groups arecovalently bonded to the polymer and/or small molecule. In otherembodiments of the present disclosure, a matrix material may provide astorage capacity for water, whereas the sequestering material is asecond material mixed with the matrix material. Regardless, as shownherein, when immersed in water, these lead-absorbing sequesteringmaterials remain structurally integrated (rather than dissolving intosmall molecules), enabling, among other things, the easy identificationand/or separation of the sequestering material containing the targetmaterial, due to, for example, the destruction of the device. As shownherein, in some embodiments of the present disclosure, greater than 99%lead sequestration of the target material can be achieved inlead-containing devices designed to include the lead-sequesteringmaterials described herein, even upon mechanical destruction of thedevices and immersion in water.

FIG. 1A illustrates a device configuration, according to someembodiments of the present disclosure. This exemplary device 100includes a typical perovskite solar cell (PSC) stack 120, including aperovskite active layer 128 positioned between an electron transportlayer 126 (e.g. TiO₂) positioned on a first conducting layer 129 (e.g.fluorine-doped tin oxide (FTO)) and a hole transport layer 124 (e.g.Spiro-OMETAD) and a second conducting layer 122 (e.g. gold). The PSCstack 120 is positioned between a first layer 110A of a sequesteringmaterial and a second layer 110B of a sequestering material. Inaddition, the device 100 of FIG. 1A includes a packaging layer 115positioned on the second layer 110B. The first layer 110A of asequestering material was applied to a substrate 129, in this example,an FTO/glass substrate. The lead-sequestering material of the firstlayer 110A included P,P′-di(2-ethylhexyl)methanediphosphonic acid(DMDP). The molecular structure of DMDP is shown above. The twophosphonic acid groups in each DMDP can strongly bind with one Pb²⁺based on the solubility constant K_(sp) value (8.1×10⁻⁴⁷) of leadphosphate.

Another possible functional group for a lead-sequestering materialincludes lead sulfate (K_(sp)=4.6×10⁻⁸). DMDP is soluble in certainpolar organic solvents (e.g., ethanol), allowing for facile filmdeposition by common coating methods (e.g., spin coating). The resultantDMDP-containing first film 110A is insoluble in water and swellsslightly when immersed in water. Nevertheless, the functional phosphonicacid groups can effectively interact with Pb²⁺ in water, for example,with lead present in water that infiltrates the device from theenvironment. For an exemplary device having a DMDP film with a thicknessof about 2.36 μm, the amount of DMDP on a molar basis (˜6.19×10⁻⁷mol/cm²) was almost twice as much as the amount of lead (3.63×10⁻⁷mol/cm²) contained in a typical PSC device, assuring adequate Pb^(2°)binding sites were provided by the DMDP material alone. In addition,DMDP is highly transparent. As shown in FIG. 2, the transmittances fordifferent thicknesses of DMDP on glass are all higher than that of pureglass (see inset). The transmittance of glass with a DMDP layer exhibitsa wavelike feature (see FIG. 1B), which is attributed to the destructiveinterference of the visible lights transmitted at different interfaces.

In the exemplary device 100 of FIG. 1A, a second film 110B of aPb-sequestering material on the back electrode side includes a stronglead-sequestering compound (e.g.,N,N,N′,N′-ethylenediaminetetrakis(methylenephosphonic acid) (EDTMP);structure shown above) mixed with a matrix material that includes apolymer to insure that the lead-free sequestering material and/or thesequestering material containing the sequestered lead cannot be removedby water. In some embodiments of the present disclosure, a matrixmaterial (e.g. a polymer; not shown), included as a part of asequestering material, may be capable of absorbing large amounts ofwater without being dissolved. Two environmentally friendly polymerssuitable that were evaluated as matrix materials for sequesteringmaterials are poly(vinyl alcohol) (PVA with molecular weight of about86,000) and poly(ethylene oxide) (PEO with a molecular weight of about2,000,000). These polymers were soaked in acetonitrile (ACN) to form aglue-like gel, to which EDTMP was added and mixed by stirring. In thisexample, the amount of EDTMP added was sufficient to provide 55 timesthe molar amount of lead present in the exemplary perovskite layer perunit area of the perovskite layer. The resultant lead-sequesteringmaterial was then converted to layers of the sequestering material(˜0.45 mm in thickness) by a “doctor blade” method. After desiccation,flexible layers of the sequestering materials made of polymer/EDTMPblends (i.e. lead-sequestering materials) were obtained, which provideda second layer 110B of lead-sequestering material on the backside of thedevice 100 positioned between the second current collector 122 (e.g. Au)and the packaging layer 115, in this case, a layer of ethylene vinylacetate (EVA).

To ensure proper comparison in this study, all devices with alead-sequestering layer and without a lead-sequestering layer werecovered by a layer of EVA on the metal electrode side unless otherwisestated. As shown in FIG. 3, the packaging layer 115 of EVA alone did notaffect the device J-V characteristics. Based on the rate and capacity ofabsorbing Pb²⁺ in water (see FIG. 4), sequestering materials made of PEOpolymer (i.e. matrix material) mixed with EDTMP (i.e. sequesteringmaterial) (denoted as EDTMP-PEO) appears to be a better choice thansequestering materials made of PVA polymers (i.e. matrix material) mixedwith EDTEMP (i.e. sequestering material) (denoted as EDTMP-PVA), whenutilized as a backside (i.e. dark side) lead-sequestering layer.Referring to FIG. 4, PEO and PVA are polymer components of sequesteringmaterials, water and ACN are solvents, and the percentages refer to theweight percentages of PEO or PVA in the solvents. For clarity, referringagain to FIG. 4, “in water” means that the sequestration film wasprepared by dissolving the matrix material and the EDTMP sequesteringmaterial in water followed by removal of the water by desiccation. “inACN” means that the sequestration film was prepared by dissolving thematrix material and EDTMP in ACN followed by removal of the ANC bydesiccation. In general, ACN worked much better as a solvent than waterfor the purpose of preparing sequestration films/layers having both amatrix material and a sequestration material.

In addition, PSCs were fabricated in three different configurations: (1)pristine control PSC devices (no lead-sequestering material included);(2) the control device plus a transparent DMDP-containing sequesteringlayer on the glass side; and (3) device (2) plus an additionalEDTMP-PEO-containing sequestering layer positioned on the metalelectrode side. All devices were covered with an EVA packaging layer (asshown in FIG. 1A). FIG. 1C illustrates J-V curves obtained for the threedifferent configurations described above. FIG. 5 illustrates thecorresponding incident photon-to-electron conversion efficiencies (IPCE)for the same device configurations. All the J-V curves with bothforward- and backward-scans in the three configurations overlap witheach other, indicating minimal affect by the layers of lead-sequesteringmaterials on device performances. The details of the PV parameters areshown in Table 1. The stable power output (SPO) efficiencies were alsoexamined and the SPO values are consistent with the measurement from theJ-V curves due to the minimum hysteresis observed for these devices (seeFIG. 6).

TABLE 1 V_(oc) J_(sc) PCE Sample (V) (mA cm⁻²) FF (%) Control (reverse)1.13 23.23 0.75 19.69 Control (forward) 1.14 23.15 0.76 20.06 Glass sidecoating (reverse) 1.13 23.38 0.76 20.08 Glass side coating (forward)1.14 23.35 0.76 20.23 Double side coating (reverse) 1.13 23.43 0.7620.12 Double side coating (forward) 1.14 23.39 0.76 20.27

FIGS. 7A, 7B, 7C, and 7D illustrate a statistical comparison of thedevice parameters (PCE, J_(sc), V_(oc), and FF, respectively) for thethree device configurations, which further confirms that the layers oflead-sequestering materials do not deteriorate PSC performance. Thelong-term stability of these devices under continuous operation undersimulated one-sun illumination intensity was also evaluated. This isespecially important for the DMDP-containing sequestering layer as it iswithin the direct optical path for light harvesting. FIG. 1D comparesthe long-term PCE for the devices based on the three configurations withand without the addition of the lead-sequestering layers. Forcomparison, all devices were covered with an EVA layer (i.e. packaginglayer) deposited on the metal electrode side. The results indicate thatthe processing and use of these exemplary lead-sequestering layers(especially the DMDP-containing sequestering layer) do not negativelyimpact long-term device performance.

The lead-sequestering capability of the DMDP-containing andEDTMP-PEO-containing layers were first evaluated by immersing theindividual layers in PbI₂ aqueous solutions and studying thetime-dependent Pb²⁺ content in the solutions. The release of lead fromsix pristine control PSCs were used as a reference to verify that theaccuracy of the measurements was within a satisfactory range. FIG. 8Aillustrates the amounts of lead released from theseperovskite-containing devices having the cell architecture shown in FIG.8B. The dashed horizontal line in FIG. 8A corresponds to the calculatedlead concentration expected as a result of the perovskite layer'sdensity and film thickness. FIG. 9 illustrates a verification curve oflead concentrations in water as measured by FAAS, which illustrates thatthe method for measuring lead to generate lead concentration datareported herein is extremely accurate and precise. (The linear curve fitis y=0.99299x with an R²=0.99957.)

FIG. 10 shows the temporal Pb²⁺ concentration profiles of 50 ml of1.93×10⁻⁵ M PbI₂ aqueous solutions (equivalent to 4 ppm of Pb²⁺ and atotal of 9.65×10⁻⁷ mol Pb²⁺, note that the maximum solubility of PbI₂ in50 ml water is 8.20×10⁻⁵ mol at room temperature) upon adding 4 cm² DMDPfilms with different thicknesses (i.e. different amounts of DMDPmolecules). In general, a 1.97-μm-thick DMDP film contains the DMDPmolecule equivalent of 2.1 times of the amount of Pb²⁺ in the aqueoussolution; thicker DMDP films provide more absorption capacity. The1.93×10⁻⁵ M PbI₂ (4 ppm Pb²⁺) was selected because the average annualrain precipitation is 77 cm in the U.S., which corresponds to about 300mL water for a 4 cm²-area. Thus, if the amount of Pb within the4-cm²-device were dissolved by the rainwater (˜300 mL), the Pbconcentration would be 4.84×10⁻⁶ M (1 ppm Pb²⁺). Hence, the use of the50 mL 1.93×10⁻⁵ M (4 ppm Pb²⁺) PbI₂ solution was intended tointentionally worsen the scenario by a factor of about 4 to test thePb-absorption capability of the DMDP film in this extreme condition.FIG. 10 illustrates no significant difference in the Pb²⁺ sequesteringcapability for DMDP layers having different thicknesses (e.g. between1.97 μm and 6.89 μm) that already contain excess DMDP with respect tothe amount of Pb²⁺ in solution. All thicker DMDP layers were capable ofdepleting Pb²⁺ concentration to the lowest detection limit (0.08 ppm) ofthe analytic method used (atomic absorption spectroscopy) within 60minutes. In contrast, the 0.7-μm-thick DMDP layer (equivalent to ˜75% ofthe amount of Pb²⁺ in solution) showed limited effect due to the lack ofsufficient binding sites. Therefore, considering the optical andcost-effectiveness, a DMDP layer having a thickness of about 2.36 μm wasselected for further studies, as disclosed herein.

Using the method described above, a comparison was completed of thePb-sequestering capabilities of EDTMP-PEO and EDTMP-PVA layers, whenimmersed in PbI₂ solutions (50 mL of 3.4×10⁻⁵ mol/L, equivalent to 7ppm). Both sequestering film compositions contained the same molaramount of EDTMP, ˜2.3×10⁻⁵ mol/cm², equivalent to 9.2×10⁻⁵ mol for a4-cm² film sample, which equates to a theoretical lead-sequesteringcapacity that was approximately 55 times the amount of Pb²⁺ contained inthe PbI₂ solutions in which the films were immersed. As discussed above,FIG. 4 illustrates that the EDTMP-PEO layer (containing 2.3×10⁻⁵ mol/cm²EDTMP) prepared by dissolving PEO in ACN provided the best results,which will be discussed further below.

The lead-sequestering layers described above were integrated with PSCsto investigate their effects on the resultant devices' ability tosequester the lead contained in the perovskite layers of the PSCs. A2.36 μm thick DMDP lead-sequestering layer and a 0.45 mm thick EDTMP-PEOsequestering layer (containing 2.3×10⁻⁵ mol/cm² EDTMP) were positionedon the glass side and the metal electrode side of PSCs (total perovskitecovered area is 2.5 cm×2.5 cm), respectively, while identical devicesabsent any lead-sequestering material were prepared for comparison. Allof the devices included an EVA layer applied to seal the metal electrodeside of the PSCs. A catastrophic failure of each of the devices wassimulated by mechanically shattering the glass side (see the photographon the left in FIG. 11A), followed by cutting the EVA layer andunderlying layers of the metal electrode (see the photograph on theright in FIG. 11A). The resultant damaged devices were each immersed in40 mL of pure water to determine the lead-sequestering capabilities ofthe DMDP and EDTMP-PEO sequestering materials. FIG. 11B illustrates thetime-dependent lead concentrations that resulted from the immersion ofthe damaged devices containing the lead-sequestering layers immersed inwater, compared to the control devices (not containing DMDP and/orEDTMP-PEO), measured at two temperatures, both room temperature and 50°C. (to mimic summer temperatures). The devices lacking lead-sequesteringlayers are indicated with asterisks.

Notably, the damaged devices containing the lead-sequestering materials,demonstrated lead loss values that remained about 0.2 ppm for both roomtemperature and 50° C., while immersed in water. These results suggestthat the sequestering materials, compositions, and/or molecules (e.g.lead-sequestering layers) described herein can be utilized toeffectively sequester various toxic elements and/or molecules, forexample lead ions released from lead-containing perovskite layerscontained in PSCs. To further track the release of lead, the leadamounts remaining in the lead-sequestering layers and in the devices asa whole were measured, after 3 hours immersed in water. As shown FIG.11C, with the lead-sequestering layers installed on both sides of thedevice, less than 2% of the lead from the perovskite layer were releasedinto the water, for both the room temperature and 50° C. temperaturetests. The top pie-chart is for data collected at 50° C. and the bottompie-chart is for data collected at room temperature. Table 2 belowsummarizes the data shown in FIG. 11C.

TABLE 2 Pb location 50° C. (%) RT (%) In water  1.9 ± 1.1  1.1 ± 0.8 Indevice  6.9 ± 1.7  8.1 ± 1.3 In DMDP 34.6 ± 2.9 50.7 ± 5.4 In EDTMP-PEO56.6 ± 1.0 40.1 ± 3.9

FIG. 12 illustrates the effect on the lead-sequestration abilities ofdamaged devices at room temperature, according to some embodiments ofthe present disclosure. The temporal lead concentrations of threecontrol devices (only sealed by EVA film on the metal electrode side)and three devices including one installed with DMDP film on the glassside alone (and the metal side is sealed with EVA), one installed withEDTMP-PEO on the metal side alone (sealed by EVA) and one with both DMDPfilm on glass side and EDTMP-PEO film on metal side (sealed by EVAfilm), according to some embodiments of the present disclosure. Allthese devices contained identical perovskite compositions, thicknesses,and areas. After intentionally damaging these devices as describedherein, lead release tests were conducted at room temperature byimmersing the damaged devices in 40 mL of pure water.

FIG. 13 illustrates the effect on the lead-sequestration abilities ofdamaged devices at 50° C., according to some embodiments of the presentdisclosure. The temporal lead concentrations of three control devices(only sealed by EVA film on the metal side) and three devices includingone installed with DMDP film on the glass side alone (and the metal sideis sealed with EVA), one installed with EDTMP-PEO on the metal sidealone (sealed by EVA) and one with both DMDP film on glass side andEDTMP-PEO film on metal side (sealed by EVA film). All these devicescontained identical perovskite, compositions, thicknesses, and areas.After intentionally damaging these devices as described herein, leadrelease tests were conducted at 50° C. by immersing the damaged devicesin 40 mL of pure water. FIG. 14 illustrates molecular modeling resultsof the binding configurations of Pb²⁺ ions with deprotonated DMDP andEDTMP. Configurations were obtained based on density functional theorycalculations.

FIG. 15A illustrates a schematic of a method for producingperovskite-containing solar cells that include layers of sequesteringmaterials, according to some embodiments of the present disclosure. Inthis exemplary method, the metal side of the PSC stack was positionedadjacent to a Pb-sequestrating EDTMP-PEO film, such that thePb-sequestrating EDTMP-PEO film was positioned between the metal sideand an EVA packaging layer (i.e. EVA film). The EVA film was softened toseal the edges of the device stack, by heat treatment, and the extra EVAon the edges were cut off to be flush with the glass surface. TheEDTMP-PEO films were made by blending PEO with EDTMP. Briefly, PEO wasdissolved in ACN at a concentration of 10 wt %; the resultant gel-likePEO solution was physically mixed with EDTMP fine powder under vigorousmechanical stirring. The resulting opaque mixture was doctor-bladed on aplastic plate, followed by desiccation, to form a PEO film containing0.01 g/cm² of EDTMP, denoted as EDTPM-PEO film, which was subsequentlypeeled off and cut into the same area as the perovskite layer andsandwiched between the metal electrodes and EVA film. The thickness(˜0.45 mm) of the dried EDTMP-PEO film was determined by a micrometer.Thereafter, the devices were spin-coated with DMDP solution on the glassside. FIG. 15B compares a pristine device (left) and a device treatedwith the DMDP solution (right) showing that directly applying the DMDPin ethanol solution damaged the perovskite stack, as made evident by theyellowing associated with perovskite decomposition due to exposure tothe polar ethanol.

FIG. 16A illustrates Pb leakage from devices in acidic water at roomtemperature, according to some embodiments of the present disclosure.The effect of Pb sequestering material on Pb leakage from the devices asa function of soaking time of damaged PSCs immersed in acidic water(pH=4.2) was examined at room temperature. The samples without any Pbsequestering material (data set with hollow triangular markers) wereused as the control. The samples with Pb sequestering material (data setwith solid triangular markers) had both sides of device stack coatedwith Pb-sequestrating films: DMDP film on glass side and EDTMP-PEO filmon metal side. All samples were covered by EVA film on the metalelectrode side. For all samples, both sides of the device stack weredamaged in the same manner and soaked in 40 mL of water (pH=4.2). Threedevices for each type of sample were measured with the averages andstandard deviations indicated. The sequestration efficiency (SQE) iscalculated for devices with Pb-sequestering materials installed on bothsides of the device, and is defined by,

${SQE}{(\%) = {\left( {1 - \frac{{Pb}\mspace{14mu}{leakage}\mspace{14mu}{from}\mspace{14mu}{devices}\mspace{14mu}{with}\mspace{14mu}{Pb}\mspace{14mu}{absorbers}\mspace{14mu}{on}\mspace{14mu}{both}\mspace{14mu}{sides}}{{Pb}\mspace{14mu}{leakage}\mspace{14mu}{from}\mspace{14mu}{devices}\mspace{14mu}{{with}{out}}\mspace{20mu}{Pb}\mspace{14mu}{absorbers}}} \right) \times 100{\%.}}}$The lead SQE after a 3-hour soaking test in acidic water is averagedabout 96.1% at room temperature.

FIG. 16B illustrates Pb leakage from devices in acidic water at 50° C.,according to some embodiments of the present disclosure. The effect ofPb sequestering materials on Pb leakage as a function of soaking time ofdamaged PSCs immersed in acidic water (pH=4.2) was examined at 50° C.The samples without any Pb sequestering material (hollow markers) wereused as the control. The samples with Pb sequestering material (solidmarkers) had both sides of device stack coated with Pb-sequestratingfilms: DMDP film on glass side and EDTMP-PEO film on metal side. Allsamples were covered by EVA film on the metal electrode side. For allsamples, both sides of the device stack were damaged in the same mannerand soaked in 40 mL of water (pH=4.2). Three devices for each type ofsample were measured with the averages and standard deviationsindicated. The acidic water test is to mimic the acidic rain condition.The lead SQE after a 3-hour soaking test in acidic water is averagedabout 97.7% at 50° C., and the SQE was not affected by the pH values oftypical acidic rains.

FIG. 16C illustrates the impact of calcium ions (Ca²⁺) on leadsequestration by DMDP, according to some embodiments of the presentdisclosure. The influence of Ca²⁺ ions (from CaCl₂) competing with leadfor sequestration was studied by soaking the DMDP samples in identicalplastic beakers, each of which contains 40 mL of water containing 12 ppmPb²⁺ and 0.1 ppm Ca²⁺ at room temperature (data set with solid squaremarkers). For the control tests, the water solution only contained Pb²⁺ions (data set with hollow square markers). Three devices for each typeof test conditions were measured with the averages and standarddeviations indicated. Ca²⁺ is a possible divalent cation in rainfall,which may affect the SQE of the sequestration materials. However, noobvious negative effects of the competitive ion (Ca²⁺) on leadsequestration by the Pb-sequestration materials used in this test wereobserved.

FIG. 16D illustrates the impact calcium ions (Ca²⁺) on Pb sequestrationby EDTMP-PEO, according to some embodiments of the present disclosure.The influence of Ca²⁺ (from CaCl₂) ions competing with lead forsequestration was studied by soaking the EDTMP-PEO samples in identicalplastic beakers, each of which contains 40 mL of water containing 12 ppmPb²⁺ and 0.1 ppm Ca²⁺ at room temperature (data set with solid circularmarkers). For the control tests, the water solution only contained Pb²⁺ions (data set with hollow circular markers). Three devices for eachtype of test conditions were measured with the averages and standarddeviations indicated. No obvious negative effect of the competitive ion(Ca²⁺) on lead sequestration is observed.

FIG. 16E illustrates a photograph of custom-made apparatus to study leadleakage from damaged devices under flowing water to simulate a rainingcondition, according to some embodiments of the present disclosure. Theflowing water was continuously dripped on the damaged devices at a rateof 5 mL per hour for 1.5 hour facilitated by a syringe pump. The damageddevices were placed in the funnel with a tilt angle of approximate 30°versus horizon. The rinsed water that contained lead was collected inplastic tubes. Flow water mimiced the dynamic rainfall motion of real,in the field, scenarios.

FIG. 16F illustrates a comparison of Pb-sequestration efficiency ofdevices at room temperature under flowing pure water (left) and acidicwater (right; pH=4.2), according to some embodiments of the presentdisclosure. Note that all devices were installed with Pb-sequesteringlayers on both sides, namely, DMDP on the glass side and EDTMP-PEO onthe metal electrode side. The Pb-sequestration efficiency isspecifically referred to these devices with both sides installed withPb-sequestering layers. Three devices for each type of test conditions(pure water and acidic water) were measured (x-axis indicates samplenumbers). The lead SQE was in the range of 96.6%-97.9% for pure waterand in a similar range of 96.7%-98.1% for acidic water.

Methods:

Materials: All solvents, chemicals were used as received without furtherrefinement except as otherwise noted and purchased from Sigma-Aldrich.P,P′-di(2-ethylhexyl)methanediphosphonic acid (DMDP) was purchased fromEichrom Technologies, Inc. PbI₂ andN,N,N′,N′-Ethylenediaminetetrakis(methylenephosphonic Acid) (EDTMP) werefrom TCI Corporation. Spiro-OMeTAD was purchased from Merck Corporation.The titanium diisopropoxidebis(acetylacetonate), tert-butylpyridine,bis(trifluoromethanesulfonyl)imide lithium saltand, Poly(ethylene oxide)(PEO, Ave. Mv=˜2000000), and Poly(vinyl alcohol) (PVA, Ave. M.W.=86000)were purchase from Sigma-Aldrich. The solar grade ethylene vinyl acetate(EVA) film was purchased from Amazon. The patterned FTO (fluorine-dopedtin-oxide-coated) glass substrates (<15Ω/square) were obtained fromAdvanced Election Technology Company.

Device Fabrication: Devices were prepared on conductive FTO glasssubstrates. The substrates were further cleaned by the cleaner,isopropanol, acetone, and ethanol, during which the substrates were alsorinsed by deionized water in between each step. A thickness of about 40nm of compact titanium dioxide layer was deposited by spray pyrolysis of7-mL isopropanol solution which contains 0.6-mL titanium diisopropoxidebis(acetylacetonate) solution (75% in isopropanol, Sigma-Aldrich) and0.4-mL acetylacetone at 450° C. in air. Then, a layer of mesoporoustitanium dioxide with the 30 nm-sized nanoparticles (30NRD, Dyesol)moderated in ethanol (1:6 w/w) was spin-coated at 4500 rpm for 15seconds on this layer followed with heating at 500° C. for 0.5 hours inair. The precursors of [(CsPbI₃)_(0.05)(FAPbI₃)_(0.85)(MAPbBr₃)_(0.15)]were dissolved in a mixed solvent of DMF/DMSO (4:1 v/v) and prepared inthe glovebox to form a 1.4 M (PbI₂ and PbBr₂). For the perovskite film,a spin-coating procedure was executed at 2000 rpm for the first 10seconds followed by 6000 rpm for the second 30 seconds. At 15 secondsbefore the end of the spin-coating procedure, 140 μL of chlorobenzenewere dropped on the substrates. The substrates were then annealed on ahotplate at 100° C. for 1 hour with a petri dish covered. Subsequently,the spiro-OMeTAD solution, which was prepared by dissolving thespiro-OMeTAD in 1-mL chlorobenzene at a concentration of 60 mM with theaddition of 30 mM bis(trifluoromethanesulfonyl)imide lithium salt from astock solution in acetonitrile and 200 mM of tert-butylpyridine, as thehole-transporting material was deposited on top of the perovskitesurface by spin coating at 4,000 rpm for 15 s. Finally, the devices werecompleted by thermal evaporation of 100-nm gold as the metal contact.

PSC packaging: All solar cells were treated in three conditions: 1)pristine devices packaged by EVA, 2) devices with DMDP on glass sidepackaged by EVA, and 3) devices with DMDP on glass side and EDTMP-PEO onmetal side packaged by EVA. For the first case, the pristine deviceswere used as the control samples without any further processing. For thesecond case, the DMDP solution, dissolved in ethanol to form a solutionat the concentration of 0.38 M, was spin-coated on the glass side ofdevices at 1000 rpm for 10 seconds. For the third case, the gold sidewas first wrapped by the EVA film with PEO-based Pb absorber layerinside. EVA film was softened to seal the edge of devices by heattreatment and the extra films on the edge were cut off to flush with theglass surface. The PEO-based Pb absorbing material was made from PEOfilms blended with EDTMP. After PEO dissolving in ACN at a concentrationof 10 wt %, the PEO solution was physically mixed with additives ofEDTMP and doctor bladed to form a PEO film, containing 0.01 g/cm² ofEDTMP, on a plastic plate. Then, the PEO-based Pb absorbing material ofthe same area as the perovskite layer was cut off and sandwiched betweenthe metal electrodes and EVA film. Thereafter, the wrapped device wasspin-coated by DMDP on the glass side.

PSC characterizations: The simulated AM 1.5 G illumination with a powerdensity of 100 mW/cm² (Oriel Sol3A Class AAA Solar Simulator) was usedto measure the solar cell performance. The current density-voltage (J-V)characteristic curves were tested using Keithley 2400 source meter. TheJ-V characteristic curves of all solar cells were measured by employinga metal mask with an activate area of 0.12 cm². Scan curves of bothbackward and forward were tested with a bias step fixing at 10 mV anddelay time fixing at 0.05 seconds. The potentiostat (Princeton AppliedResearch, Versa STAT MC) was employed to measure the continuous currentand power output. Incident photon-to-electron conversion efficiency(IPCE) spectra of solar cells were measured using a solar cellquantum-efficiency measurement system (QEX10, PV Measurements).

Pb absorption characterizations: The optical transmission spectroscopywas carried out with UV-VIS spectrophotometer (UV-2600, ShimadzuScientific Instruments, Inc.) at a spectral range of 300 to 1100 nm. Theprepared DMDP solutions with the concentration of 0.19 M, 0.38 M, 0.57M, and 0.76 M to attain different thicknesses, respectively werespin-coated on the glass substrates (VWR International, LLC.) at 1000rpm for 10 seconds for subsequent transmittance measurements. Thethickness was determined by mass based on the density of DMDP (1.05g/mL).

Atomic Absorption Flame Emission Spectrophotometer (FAAS) was conductedwith an AA-6200 (Shimadzu Scientific Instruments, Inc.), equipped with aPb hollow cathode lamp as a radiation source where the resonance linewavelength is 217 nm. Air/acetylene flame with a fuel rate of 2 L/min,lamp current of 12 mA with a slit width of 0.7 nm under mode of BGC-D2were applied. A calibration curve made by PbI₂ aqueous solutions fordetermination of the Pb content in deionized water as a standard wasreferenced by all sample tests. All samples were delivered to theinstrument by clean syringes with a filter to avoid solids debris thatcan affect the flame per manufacturer's instruction. For preliminaryevaluation of the absorption capacity of DMDP, the size of 2×2 cm² glasssubstrates were spin-coated with DMDP solutions first. For eachconcentration, gradient spin rates, ranging from 500 to 4000rpm, wereemployed to form the transparent layers with different thicknesses.Then, each DMDP-coated glass substrate was dipped into 50 mL 4 ppmaqueous PbI₂ solutions for time-dependent Pb-absorption measurements.Similarly, for preliminary evaluation of Pb-absorbing films used on themetal electrode side, each film with a size of 2×2 cm² was soaked into50 mL 7 ppm aqueous PbI₂ solutions for time-dependent Pb-absorptionmeasurements. The Pb amount in the DMDP film is determined by dissolvingthe films in ethanol.

FIRST EXAMPLE SET

Example 1. A composition comprising: a sequestering material capable ofbinding a target material, wherein: the sequestering material comprisesa first component comprising at least one of a functional group, amolecule, an oligomer, or a polymer, and the target material comprisesat least one of an element, a chemical, or a compound.

Example 2. The composition of Example 1, wherein the binding comprisesat least one of chelation, reacting, ionically interacting, orphysically adsorbing.

Example 3. The composition of Example 1, wherein the element comprisesat least one element from at least one of Rows 4, 5, 6, and 7 of thePeriodic Table or an inner transition metal.

Example 4. The composition of Example 1, wherein the element comprisesat least one of cadmium, lead, tin, germanium, bismuth, thallium,chromium, mercury, antimony, or arsenic.

Example 5. The composition of Example 1, wherein the target materialcomprises at least one of lead, tin, germanium, cadmium, copper, indium,gallium, mercury, bismuth, chromium, iron, copper, zinc, aluminumberyllium, ruthenium, nickel, cobalt, manganese, silver, thallium,indium, antimony, germanium, selenium, tellurium, or arsenic.

Example 6. The composition of Example 1, wherein the target materialcomprises at least one of lead, tin, germanium, cadmium, copper, indium,gallium, mercury, bismuth, chromium, iron, copper, zinc, aluminumberyllium, ruthenium, nickel, cobalt, manganese, silver, thallium,indium, antimony, germanium, selenium, tellurium, arsenic, iodine,bromine, chlorine, or fluorine.

Example 7. The composition of Example 1, wherein the target material isin any valence state.

Example 8. The composition of Example 7, wherein the target materialcomprises lead.

Example 9. The composition of Example 8, wherein the target materialcomprises Pb²⁺.

Example 10. The composition of Example 1, wherein a chemical comprisesat least one of sulfate, acetate, chromate, dichromate, nitrate,permanganate, carbonate, citrate, cyanide, or phosphate.

Example 11. The composition of Example 1, wherein the first componentcomprises at least one of hydrogen, phosphorus, nitrogen, sulfur,oxygen, carbon, or silicon.

Example 12. The composition of Example 11, wherein the first componentcomprises at least one of an amine group, an amide group, a hydrazinegroup, an isocyanate group, a nitrile group, a nitrite group, an aminogroup, an imino group, an imido group, a hydrazine group, a cyanategroup, an isocyano group, an isocyanato-nitrooxy group, a cyano group, anitrosooxy group, a nitroso group, a pyridyl group, or a carboxamidogroup.

Example 13. The composition of Example 11, wherein the first componentcomprises at least one of a thiol group, a sulfide group, a disulfidegroup, a sulfoxide group, a sulfone group, a sulfinic acid group, asulfonic acid group, a thiocyanato group, a mercapto group, a sulfanylgroup, a sulfinyl group, a sulfo group, a sulfonyl group, anisothiocyanato group or a disulfide group.

Example 14. The composition of Example 11, wherein the first componentcomprises at least one of a hydroxyl group, a carbonyl group, acarboxylate group.

Example 15. The composition of Example 11, wherein the first componentcomprises at least one of a silicate group, a siliconate group, a silanegroup, or a siloxane.

Example 16. The composition of Example 11, wherein the first componentcomprises at least one of a phosphonic group, a phosphate group, aphosphoryl group, a phosphono group, a phosphor group, or a phosphorylgroup.

Example 17. The composition of Example 16, wherein: the first componenthas a structure defined by

and each of R₁, R₂, and R₃ comprise at least one of hydrogen, oxygen, orcarbon.

Example 18. The composition of Example 17, wherein: the structure isdefined by

and both R₄ and R₅ comprise at least one of hydrogen, oxygen, or carbon.

Example 19. The composition of Example 18, wherein: the structure isdefined by

and both R⁶ and R comprise at least one of hydrogen, oxygen, or carbon.

Example 20. The composition of Example 19, wherein: the structure isdefined by

Example 21. The composition of Example 1, wherein the first componentcomprises at least one of P,P′-di(2-ethylhexyl)methanediphosphonic acid(DMDP) or N,N,N′,N′-ethylenediaminetetrakis(methylenephosphonic acid)(EDTMP).

Example 22. The composition of Example 1, wherein the first componentcomprises at least one of DMDP, EDTMP, dimercaptosuccinic acid (DMSA),ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA),ethylenediaminedisuccinic acid (EDDS), iminodisuccinic acid (IDS),methylglycine diacetic acid (MGDA), L-Glutamic acid N,Ndiacetic acid(GLDA), 2-hydroxyethyliminodiacetic acid (HEIDA),ethylenediamine-N,N′-dimalonic acid (EDDM),ethylenediamine-N,N′-diglutaric acid (EDDG),3-hydroxy-2,2-iminodisuccinic acid (HIDS), and/or 2,6-pyridinedicarboxylic acid (PDA), poly ethylene glycol (PEG), poly vinyl alcohol,poly vinyl pyrrolidone, or a cellulose-based material.

Example 23. The composition of Example 1, wherein the first componentcomprises at least one of poly(vinyl alcohol) (PVA), poly(ethyleneoxide) (PEO), a polyacrylate, a derivative of a polyacrylate,polyvinylpyrrolidone, an oxide, a glass, or a silicone gel.

Example 24. The composition of Example 1, wherein the sequesteringmaterial has first a capacity to bind the target material at a firstratio between about 0.001 grams of the target material per gram of thesequestering material and about 100 grams of the target material pergram of the sequestering material.

Example 25. The composition of Example 24, wherein the first ratio isbetween about 0.01 and 10.

Example 26. The composition of Example 1, wherein the sequesteringmaterial is substantially transparent to light having a wavelengthbetween about 300 nm and about 1200 nm.

Example 27. The composition of Example 1, wherein the sequesteringmaterial has a solubility product constant value, K_(sp), for the targetmaterial between about 10⁻⁶⁰ and about 1.

Example 28. The composition of Example 1, wherein the sequesteringmaterial has second a capacity absorb water at a second ratio betweenabout 0.01 grams of water per gram of the sequestering material andabout 100 grams of water per gram of the sequestering material.

Example 29. The composition of Example 1, wherein the sequesteringmaterial has second a capacity absorb water at a second ratio betweenabout 0.1 grams of water per gram of the sequestering material and about100 grams of water per gram of the sequestering material.

Example 30. The composition of Example 1, wherein the sequesteringmaterial further comprises a matrix material.

Example 31. The composition of Example 30, wherein the sequesteringmaterial and the matrix material are at least one of covalently bondedor ionically bonded to each other.

Example 32. The composition of Example 30, wherein the matrix materialcomprises at least one of a polymer or an oligomer.

Example 33. The composition of Example 30, wherein the matrix materialcomprises at least one of PVA, PEO, a polyacrylate, a derivative of apolyacrylate, polyvinylpyrrolidone, an oxide, a glass, or a siliconegel.

Example 34. The composition of Example 30, wherein the first componentand the matrix material are present at a second ratio between about0.001 grams of the first component per gram of the matrix material andabout 100 grams of the first component per gram of the matrix material.

Example 35. The composition of Example 34, wherein the first componentand the matrix material are present at a second ratio between about 0.01grams of the first component per gram of the matrix material and about10 grams of the first component per gram of the matrix material.

Example 36. The composition of Example 30, wherein the sequesteringmaterial is substantially transparent to light having a wavelengthbetween about 300 nm and about 1200 nm.

Example 37. The composition of Example 30, wherein the sequesteringmaterial has a solubility product constant value, K_(sp), for the targetmaterial between about 10⁻⁶⁰ and about 1.

Example 38. The composition of Example 30, wherein the sequesteringmaterial has second a capacity to absorb water at a second ratio betweenabout 0.01 grams of water per gram of the sequestering material andabout 100 grams of water per gram of the sequestering material.

Example 39. The composition of Example 38, wherein the sequesteringmaterial has second a capacity absorb water at a second ratio betweenabout 0.1 grams of water per gram of the sequestering material and about100 grams of water per gram of the sequestering material.

Example 40. The composition of Example 1, wherein: the sequesteringmaterial is present in a continuous phase, and the target material ispresent in a phase dispersed within the continuous phase.

Example 41. The composition of Example 1, wherein: the target materialis present in a continuous phase, and the sequestering material ispresent in a phase dispersed within the continuous phase.

Example 42. The composition of either Example 40 or 41, wherein thecomposition is used as at least one of a coating or a paint.

SECOND EXAMPLE SET

Example 1. A device comprising: a first feature comprising asequestering material; and a second feature comprising a targetmaterial, wherein: the sequestering material is capable of binding thetarget material, the sequestering material comprises a first componentcomprising at least one of a functional group, a molecule, an oligomer,or a polymer, and the target material comprises at least one of anelement, a chemical, or a compound.

Example 2. The device of Example 1, wherein the device comprises atleast one of a photovoltaic device, an electronic device, anoptoelectronic device, or a building structure.

Example 3. The device of Example 1, wherein the photovoltaic devicecomprises at least one of a feature of a solar cell, a solar cell, asolar panel, a solar module, or a solar array.

Example 4. The device of Example 2, wherein the device comprises atleast one of a sensor, a light-emitting diodes, a solar window, asensor, a display, or a memristor.

Example 5. The device of Example 1, wherein at least one of the firstfeature or the second feature has a three-dimensional shape comprisingat least one of an amorphous particle, a planar structure, a sphere, acylinder, a cuboid, a cone, a pyramid, or a polyhedron.

Example 6. The device of Example 1, wherein: the first feature comprisesa coating containing the sequestering material, the second featurecomprises a building structure containing the target material, and thebuilding structure comprises a surface substantially covered by thecoating.

Example 7. The device of Example 6, wherein the building structurecomprises at least one of a wall, a ceiling, a floor, or a pipe.

Example 8. The device of Example 3, wherein: the first feature comprisesa first planar structure, the second feature comprises a second planarstructure, and the first planar structure and the second planarstructure are adjacent and substantially parallel to one another.

Example 9. The device of Example 8, wherein the second planar structurecomprises at least one of an active material or a charge-transportmaterial.

Example 10. The device of Example 9, wherein the active materialcomprises a semiconductor.

Example 11. The device of Example 10, wherein the semiconductor isphotovoltaic.

Example 12. The device of Example 11, wherein the active materialcomprises at least one of a perovskite, a polymer, a III-V alloy,cadmium, tellurium, copper, indium, gallium, selenium, or silicon.

Example 13. The device of Example 12, wherein the perovskite comprisesat least one of a zero-dimensional perovskite, a one-dimensionalperovskite, a two-dimensional perovskite, or a three-dimensionalperovskite.

Example 14. The device of Example 13, wherein the perovskite comprisesat least three of a first cation (A), a second cation (B), and an anion(X).

Example 15. The device of Example 14, wherein the perovskite has astructure comprising ABX₃.

Example 16. The device of Example 14, wherein A comprises at least oneof an alkylammonium, formamidinium, cesium, hydrazinium, acetylammonium,imidazolium, or guanidinium.

Example 17. The device of Example 16, wherein the alkylammoniumcomprises at least one of dimethylammonium, methylammonium,ethylammonium, or butylammonium.

Example 18. The device of Example 14, wherein B comprises at least oneof lead, tin, or germanium.

Example 19. The device of Example 14, wherein X comprises a halogen.

Example 20. The device of Example 13, further comprising a third cation(M), wherein M comprises at least one of butylammonium,phenylethylammonium, cyclopropylammonium, polyethylenimine,iodoethylammonium, ethane-1,2-diammonium, or ammoniumvaleric acid.

THIRD EXAMPLE SET

Example 1. A method for sequestering a target material, the methodcomprising: applying a composition comprising a sequestering material toa device having a feature comprising the target material, wherein: overa period of time, a portion of the target material is removed from thefeature due to exposure to the environment, and the sequesteringmaterial binds the portion of the target material, preventing itsleakage into the environment.

Example 2. The method of Example 1, further comprising, at theconclusion of the period of time, recovering the target material fromthe sequestering material.

Example 3. The method of Example 1, wherein the period of time isbetween one month and 100 years.

The foregoing discussion and examples have been presented for purposesof illustration and description. The foregoing is not intended to limitthe aspects, embodiments, or configurations to the form or formsdisclosed herein. In the foregoing Detailed Description for example,various features of the aspects, embodiments, or configurations aregrouped together in one or more embodiments, configurations, or aspectsfor the purpose of streamlining the disclosure. The features of theaspects, embodiments, or configurations, may be combined in alternateaspects, embodiments, or configurations other than those discussedabove. This method of disclosure is not to be interpreted as reflectingan intention that the aspects, embodiments, or configurations requiremore features than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive aspects lie in less than allfeatures of a single foregoing disclosed embodiment, configuration, oraspect. While certain aspects of conventional technology have beendiscussed to facilitate disclosure of some embodiments of the presentinvention, the Applicants in no way disclaim these technical aspects,and it is contemplated that the claimed invention may encompass one ormore of the conventional technical aspects discussed herein. Thus, thefollowing claims are hereby incorporated into this Detailed Description,with each claim standing on its own as a separate aspect, embodiment, orconfiguration.

What is claimed is:
 1. A photovoltaic device comprising: a perovskitelayer comprising at least one of lead, tin, or bismuth; and asequestering material layer capable of binding at least one of lead,tin, or bismuth, wherein: the sequestering material layer comprises afirst component comprising at least one of a phosphonic group, aphosphate group, a phosphono group, a phosphor group, a phosphorylgroup, a hydroxyl group, or a carboxylic acid group.
 2. The photovoltaicdevice of claim 1, wherein the lead is in a form comprising Pb²⁺.
 3. Thephotovoltaic device of claim 1, wherein the first component furthercomprises at least one of hydrogen, nitrogen, sulfur, carbon, orsilicon.
 4. The photovoltaic device of claim 1, wherein: the firstcomponent is defined by a structure comprising


5. The photovoltaic device of claim 1, wherein the first componentcomprises at least one of P,P′-di(2-ethylhexyl)methanediphosphonic acid,N,N,N′, N′-ethylenediaminetetrakis(methylenephosphonic acid),dimercaptosuccinic acid, ethylenediaminetetraacetic acid,nitrilotriacetic acid, ethylenediaminedisuccinic acid, iminodisuccinicacid, methylglycine diacetic acid, L-Glutamic acid N,Ndiacetic acid,2-hydroxyethyliminodiacetic acid, ethylenediamine-N,N′-dimalonic acid,ethylenediamine-N,N′-diglutaric acid, 3-hydroxy-2,2-iminodisuccinicacid, 2,6-pyridine dicarboxylic acid, polyethylene glycol, polyvinylalcohol, or a cellulose-based material.
 6. The photovoltaic device ofclaim 1, wherein the sequestering material layer further comprises amatrix material.
 7. The photovoltaic device of claim 6, wherein thematrix material comprises at least one of a polymer or an oligomer. 8.The photovoltaic device of claim 6, wherein the matrix materialcomprises at least one of a poly(vinyl alcohol), a poly(ethylene oxide),a polyacrylate, a derivative of a polycrylate, a polyvinylpyrrolidone,an oxide, a glass, or a silicone gel.
 9. The photovoltaic device ofclaim 6, wherein the first component and the matrix material are presentat a first ratio between about 0.001 grams of the first component pergram of the matrix material and about 100 grams of the first componentper gram of the matrix material.
 10. The photovoltaic device of claim 6,wherein the sequestering material layer is substantially transparent tolight having a wavelength between about 300 nm and about 1200 nm. 11.The photovoltaic device of claim 6, wherein the sequestering materiallayer has a solubility product constant value, K_(sp), for at least oneof lead, tin, or bismuth between about 10⁻⁶⁰ and about
 1. 12. Thephotovoltaic device of claim 6, wherein the sequestering material layerhas a capacity to absorb water at a second ratio between about 0.01grams of water per gram of the sequestering material layer and about 100grams of water per gram of the sequestering material layer.